Genomic testing the key to determining source of Auckland COVID-19 outbreak, says expert

Confidence is brimming in one genome sequencing expert about New Zealand's ongoing response to COVID-19.

Dr Jemma Geoghegan from the University of Otago says although one of New Zealand's COVID-19 cases is not linked to the Auckland cluster, there's no need to panic.

"We have signs that the genome matches one from a hotel worker. So there is a link there that's linked to a returning traveller," she told Newshub. 

The positive case is a maintenance worker at the Rydges in Auckland.

Dr Geoghegan says genomic testing will be key to the Government's COVID-19 response.

"People have started to realise the importance of it and it's place in this response is really powerful especially when we don't know the source of an outbreak."

She describes genomic testing as reconstructing a "family tree" for the virus, to trace where it originated.

"When a virus is passed from human to human the virus changes or mutates slightly so these mutations are picked up from one person to another," she said.

"By reconstructing the genome of all the cases in New Zealand we can more accurately determine the source of the outbreak."

At this point the source of Auckland's outbreak is still unknown - one theory is it could have been shipped in with the freight handled by the first man who contracted it - a worker at Americold in his 50s. 

Testing of the strain of COVID-19 contracted by the man's family suggested the strand originated in the UK or Australia, but it was not clear how it ended up in Auckland.

Since last Tuesday, New Zealand has recorded 70 cases of community transmission, with all but two detected in Auckland. Two were recorded in Tokoroa.